title: The centriolar satellite protein SSX2IP promotes centrosome maturation.
abstract: Meiotic maturation in vertebrate oocytes is an excellent model system for microtubule reorganization during M-phase spindle assembly. Here, we surveyed changes in the pattern of microtubule-interacting proteins upon Xenopus laevis oocyte maturation by quantitative proteomics. We identified the synovial sarcoma X breakpoint protein (SSX2IP) as a novel spindle protein. Using X. laevis egg extracts, we show that SSX2IP accumulated at spindle poles in a Dynein-dependent manner and interacted with the γ-tubulin ring complex (γ-TuRC) and the centriolar satellite protein PCM-1. Immunodepletion of SSX2IP impeded γ-TuRC loading onto centrosomes. This led to reduced microtubule nucleation and spindle assembly failure. In rapidly dividing blastomeres of medaka (Oryzias latipes) and in somatic cells, SSX2IP knockdown caused fragmentation of pericentriolar material and chromosome segregation errors. We characterize SSX2IP as a novel centrosome maturation and maintenance factor that is expressed at the onset of vertebrate development. It preserves centrosome integrity and faithful mitosis during the rapid cleavage division of blastomeres and in somatic cells.
authors.affiliation: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Bärenz
authors.forename: Daigo
authors.initials: D
authors.lastname: Inoue
authors.forename: Hideki
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Justus
authors.initials: J
authors.lastname: Tegha-Dunghu
authors.forename: Stephanie
authors.initials: S
authors.lastname: Freiss
authors.forename: Stefanie
authors.initials: S
authors.lastname: Draeger
authors.forename: Dmytro
authors.initials: D
authors.lastname: Mayilo
authors.forename: Ivana
authors.initials: I
authors.lastname: Cado
authors.forename: Sabine
authors.initials: S
authors.lastname: Merker
authors.forename: Maren
authors.initials: M
authors.lastname: Klinger
authors.forename: Burkhard
authors.initials: B
authors.lastname: Hoeckendorf
authors.forename: Sahra
authors.initials: S
authors.lastname: Pilz
authors.forename: Kerstin
authors.initials: K
authors.lastname: Hupfeld
authors.forename: Herbert
authors.initials: H
authors.lastname: Steinbeisser
authors.forename: Holger
authors.initials: H
authors.lastname: Lorenz
authors.forename: Thomas
authors.initials: T
authors.lastname: Ruppert
authors.forename: Joachim
authors.initials: J
authors.lastname: Wittbrodt
authors.forename: Oliver J
authors.initials: OJ
authors.lastname: Gruss
mesh_terms: D000818:Animals; D001757:Blastomeres / Q000378:metabolism / Q000473:pathology; D002502:Centrioles / Q000235:genetics / Q000378:metabolism*; D018385:Centrosome / Q000378:metabolism*; D020090:Chromosome Segregation; D002875:Chromosomes / Q000235:genetics / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D055785:Gene Knockdown Techniques; D008938:Mitosis; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D009990:Oryzias / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism; D059008:Time-Lapse Imaging; D014404:Tubulin / Q000235:genetics / Q000378:metabolism; D029867:Xenopus Proteins / Q000378:metabolism*; D014982:Xenopus laevis / Q000235:genetics / Q000378:metabolism*
chemical_list: D009363:Neoplasm Proteins; D012097:Repressor Proteins; D014404:Tubulin; D029867:Xenopus Proteins; C093962:synovial sarcoma X breakpoint proteins